U.S.-led forces and Afghan police say they have killed five militants during a gun battle at a checkpoint in southern Afghanistan.

Military officials say militants in three vehicles opened fire at troops late Tuesday at the checkpoint in Maruf district in Kandahar province. The troops returned fire, killing five militants. No coalition or Afghan forces were wounded.

Elsewhere in eastern Nangarhar province Wednesday, more than 1,000 Afghans protested for a fourth day over the alleged killing of civilians by U.S.-led coalition troops.

Afghan villagers say six people were killed there Sunday during a raid by coalition and Afghan forces. But the coalition says four of the dead were militants.

Meanwhile, Afghan officials say between 40 and 51 civilians have been killed during recent coalition raids in Herat in western Afghanistan.

The Associated Press quotes a U.S. coalition official as saying there have been no reports of civilian deaths.

Civilian deaths have been a major issue in Afghanistan, with NATO admitting the killing of civilians was their biggest mistake in 2006.

Over the past year, Taleban insurgents have dramatically increased their attacks on Afghan officials, and NATO and U.S.-led coalition troops.

Some information for this report was provided by AFP, AP and Reuters.